Question

Ao calcular a multiplicação (x+2) (2x+1), obtém-se:

( ) A (A) 2X²+2
( ) B (B) 3X²+3
( ) C (C) 2X²+5X+2
( ) D (D) 3X²+6X+3

Answer 1

Aplicando a regra distributiva:
$\left(a+b\right)\left(c+d\right)=ac+ad+bc+bd$

$\left(x+2\right)\left(2x+1\right)$
$=x\cdot \:2x+x\cdot \:1+2\cdot \:2x+2\cdot \:1$
Simplificando:
$2x^2+5x+2$